Liver cancer is the 5th most common cancer (748,000 cases a year) and the 3rd most common cause of cancer death (695,000 deaths a year) in the world. In the United States, while the incidence of many major cancers is declining, the incidence of hepatocellular carcinoma (HCC), the most common type of liver cancer, has almost tripled over the past two decades to ~20,000 per year. Despite the success of HBV vaccines to prevent new HBV infection, the large pool of existing HBV (350 million) and HCV (170 million) patients and the recent recognition that obesity/diabetes become a major risk factor of HCC in US suggest that HCC incidence will continue increasing over next few decades. Unfortunately, treatment options for HCC are limited, contributing to the dismal 17% 3-year survival rate. Liver resection and transplantation are curative for small tumors. But, the lac of adjuvant treatments after surgery is a critical barrier to the success of liver resection, which results in ~70% 5-year recurrence rate. Thus, there is an urgent need to develop novel approaches for HCC. Our long-term goal is to develop HCC vaccines to activate patient's immune system to conduct immune surveillance and thereby prevent HCC relapse or de novo development in high risk population. Approximately 84% of HCC (but not normal hepatocytes) express alpha fetoprotein (AFP), glypican 3 (GPC3), or both, making them excellent immune targets. However, they are self/tumor antigens and weakly immunogenic, and thus cannot effectively activate immune cells to generate significant antitumor effect. In this application, we propose to use murine autochthonous models to test the hypotheses that innovative approach of antigen engineering will increase the immunogenicity of HCC-associated self/tumor antigens of AFP and GPC3 to create effective HCC vaccines and that novel immunization strategy with the engineered HCC vaccines will induce potent and highly responsive memory T cells that conduct immune surveillance to prevent autochthonous HCC. The objectives are 1) to create immunogenic HCC vaccines, 2) to establish effective immunization strategy, and 3) to prevent autochthonous HCC. The outcomes will be the effective activation of immune system to prevent autochthonous HCC and generation of critical preclinical data that will help development of human HCC vaccine, which eventually lead to new therapy to fill the gap of HCC management after surgery. This will greatly benefit HCC patients who have undergone liver resection by preventing relapse and also offer an attractive option to prevent HCC de novo development in high risk populations who are living in the fear of developing HCC. This will bring about a radical change of HCC management, shifting the focus of cancer vaccine research from therapy to prevention, which is what a vaccine does best.